Did Debbie Reynolds die of a broken heart? Yes most likely the stress contributed to her death.

Debbie Reynolds was a huge movie star in the 1950s and 60s. She broke through with a career-making performance in the classic musical "Singing in the Rain" at the young age of 19 (Figure 1). By 23 she was one of the top stars in Hollywood and married to Eddie Fisher, who was also a big pop music and movie star at the time. They had two children, a son Todd and a daughter Carrie.

Ms Reynolds daughter Carrie Fisher grew up in the shadow of her famous Mom, but broke through in 1977 with a starring performance in one of the most influential movies of all-time: Star Wars. At the tender age of 21, she was an international star, and her fame at the time eclipsed that of even her Mother. The subsequent years were turbulent both personally and professionally as she struggled with bipolar disorder and drug addiction.

Indeed her honest and open account of her own mental illness made her an influential spokesperson for mental health issues. Ms Fisher also described her tumultuous relationship with her Mother which by all accounts was very close but marked by periods of estrangement. Fortunately, they achieved a reconciliation and remained close until the end.

Approximately a month ago, Ms Fisher died suddenly of heart failure on a flight from London back to Los Angeles. She was 60. The shock of her death was amplified when the following day her mother Debbie Reynolds died of a stroke.

The next day a front page story of  The New York Times asked "Did Debbie Reynolds die of a broken heart?" In a figurative sense she did; in a literal sense, she died of stroke and was ailing at the time (she was 84). However, the close proximity of the events is very suggestive of a causal influence, and as I describe below there is abundant scientific data that support this hypothesis

First most generally (STAT), people who have lost a loved one are more likely to die than a control person who is not bereaved. A study in Denmark examined mortality in parents after a child had died. The total hazard ratio in the first 3 years after death for mothers was 1.58 (1.58 times greater chance than a person whose child had not died), but much of that increased mortality was due to unnatural deaths (3.84 hazard ratio) compared to natural deaths (1.06). Unnatural deaths include events such as accidents, suicide, and drug overdose. It is formally possible that Ms Reynolds died an unnatural death, but then her death was reported as a natural death (i.e. stroke).

Then looking more specifically at cardiovascular events, a person who lost a loved one in the past month is twice as likely to die of a heart attack or stroke as a control non-grieving person, although the overall percentage is very small (STAT):

"A study published in JAMA Internal Medicine in 2014 found that people who had lost a loved one in the past month were twice as likely to suffer a heart attack or stroke as their peers who weren’t grieving. It happened quite rarely, though — just 0.16 percent of those in the grieving group had a heart attack or stroke, compared to 0.08 percent in the control group."

Finally if we focus on stroke, researchers found that "[p]ermanent self-perceived psychological stress during the last year or longer was independently associated with overall ischemic stroke" with an adjusted odd-ratio of 3.49. In other words, people who felt that they were under psychological stress were roughly 3.5 times more likely to have ischemic stroke (caused by a clot) than those who were not under stress. The death of one's beloved daughter would cause a tremendous amount of stress.

It is known that stress can induce high blood pressure. The release of stress hormones such as adrenaline (epinephrine) and norepinephrine can raise blood pressure by increasing the heart rate and constricting blood vessels. Drugs (beta-blockers) that counteract the action of these hormones on the adrenergic receptors represent one of the main classes of medication used to treat hypertension.

High blood pressure causes damage to blood vessels which leads to atherosclerosis and general weakening of the vessel wall, which can produce a clot or rupture (aneurysm) in the brain resulting in stroke (ischemic or hemorrhagic). The risk increases with age as the resilience of your circulatory system declines. The damage induced by hypertension accumulates over time, but a sudden shock to the system may disrupt an already weakened system on a shorter time frame.

In summary, the very close temporal proximity (one day separation) of the two events is highly suggestive that yes. the stress of her beloved daughter's death played a major role in Debbie Reynolds' stroke (if indeed she did die of stroke). As summarized above, there is a substantial body of medical evidence that supports this connection.

Figure 1. Debbie Reynolds starring in Singing in the Rain along with Gene Kelly and Donald O'Connor.